Taxonomic Hierarchy

Classifying organisms into successive levels of biological classification in descending or ascending order from kingdom to species and vice versa is known as a taxonomic hierarchy. The taxonomic category or rank corresponds to each level of the hierarchy. Theophrastus wrote the first important text on taxonomy sometime around 300 BC. Carolus Linneaus (1707–1778), the pioneer of taxonomy (father of taxonomy), is still revered.

Importance of Taxonomy 

• Plant elements or taxa should be organised more systematically to understand them better and use them more readily and efficiently. 
• To organise data, information, and plant knowledge. 
• To identify the source of plants and their genetic relationship (phylogenetic), ancestry, and origin. 
• To show the distribution and habitat of plants and their advantages.

Taxonomic Characters

• Morphology 

Plant development habits, leaf arrangement, and form, flower and fruit characteristics are essential factors to consider. 

• Physiology 

The epidermis, which includes trichomes and stomata, has secondary xylem features. 

• Palynology

Size, shape, aperture, and exine sculpting are all properties of pollen.

• Cytology 

The number, structure, and behaviour of chromosomes

• Chemical and molecular 

Chemical and molecular content of alkaloids, phenolic acids, and amino acids DNA, protein, and enzymes.

Taxonomic Components 

• Categorisation

Plants are classified according to comparable traits. The taxonomic system is composed of groups classified as categories of taxa. 

• Identification 

By referring to an existing taxonomy, you can identify and determine the name of an organism. 

• Nomenclature 

To give an organism a scientific name. 

• Description

To describe a taxon’s characteristics, such as a family.

Kingdom 

The classification’s highest level or rank is the kingdom. The highest category in the animal categorisation scheme is Kingdom Animalia, which includes all creatures belonging to various phyla. On the other hand, the Kingdom Plantae is unique and includes all plant divisions.

Division

The division is the next level of classification, with several classes. This taxon’s number of groups is not fixed; the classification system determines it. It’s based on morphological and anatomical similarities found in a few elements or organs, such as sporophyte dominance over gametophyte, ovule presence, seed production, and other morphological and anatomical features. Those are inherited traits that will pass down the generations.

Class

A class is a collection of orders that have little in common. The number of taxon groups also varies depending on the classification system. Separation is predicated on significant fundamental distinctions between the groupings.

Order

Order refers to groups of families that have less in common. Separation is predicated on a stronger genetic link previously discovered at the class and division levels.

Family

Several genera make up the family, all of which are linked in some way. Order, class, and division are less significant than the physical qualities of reproductive organs (inflorescence, ovary position, placentation, number of pistils and carpels, morphologies of ovule and androecium).

Genus

Multiple species in a genus have similar traits, yet they differ from species in other genera. Genus shares more similarities, such as a closer family link, but they do not intersect. In the event of a hybrid cross, the progeny are usually sterile or do not survive. A new genus emerges and separates phylogenetically.

Species

The lowest classification level, species, demonstrates a high similarity among creatures.

Morphological concept of species

The smallest collection of creatures that morphological traits can reliably distinguish is called a species. Because it is the most practical, taxonomists commonly use the notion.

The Biological Concept of Species

Species are defined by their reproductive biology. A species is a population group capable of reproducing but not exchanging genes with populations of other species. Self-pollinated or asexually generated species are not eligible. 

An Example: Taxonomic Hierarchy of Banana

• KINGDOM: Plantae
• DIVISION: Magnoliophyta/Spermatophyta
• CLASS: Liliopsida/Monocotyledons
• ORDER: Zingiberales
• FAMILY: Musaceae
• GENUS: Musa
• SPECIES: Musa acuminata

Sub and Super Categories 

There are infra taxa that characterise variations inside a taxon, in addition to the seven primary categories: 

FAMILY, Subfamily, Tribe, Subtribe, GENUS, Subgenus, Section, Subsection, Series, Subseries, SPECIES, Subspecies, Variety, Subvariety, Form, Subform, KINGDOM, Subkingdom, DIVISION, Subdivision, CLASS, Subclass, (Superorder), ORDER, Suborder, FAMILY, Subfamily, Tribe, Subtribe, GENUS, Subgenus, Section, Subsection, Series.

Subspecies and Variety

Morphological changes within a species can be detected as a result of adaptation to diverse environments. Only minor modifications are classified as forms. The cultivar results from multiple generations of cross-breeding and does not occur naturally. A clone is a uniform population of genetically identical plants to the mother plant and is generated asexually or naturally.

Advantages of the Taxonomic hierarchy

• It is possible to classify living organisms into different categories based on their degrees of diversity. 
• This categorisation aids in the classification of a specific collection of plants into suitable classes.

Conclusion 

Taxonomy is the science of naming, describing, and classifying species and includes all plants, animals, and microbes. Classifying organisms into successive levels of biological classification, either in decreasing or increasing order, from kingdom to species and vice versa, is known as a taxonomic hierarchy. Plant elements, or taxa, should be organised more systematically to be better understood and used more quickly and effectively.